Improved process for treating auriferous ores



yphureted hydrogen.

-UNITED STATES.

w. ADOLF OTT, OF BROOKLYN, EW YORK, ASSIGNOB rrO HIMSIELFAND r HENRYJAOKSOROF SAME PLACE.

IMPROVED PROCESS FOR TREATING AURIFEROUS-ORES. 1

Specification forming part of Letters Patent 0. 4 7,497; dated April 25, 18(i5.

To allwhont it may concern.-

Be it known that I, W. ADOLF O'rr, of Brooklyn, in the county of Kings, and State of New York, have invented a new and Improved Process for Treating Auriferous and other Ores; and I do hereby declare that the following is a full, clear, and exact description of the same.

This invention consists in the employment or use of a mixture of hypochlorous acid in extracting gold from auriferous ores, and particularly from pyrites containing goldn In order to carry out my process, I prepare the ore by stamping the same and roasting it until all the metal salts contained therein are transformed into sulphates; or, if the ore consists of a mixture of sulphide of copper and sulphide of iron containing much sulphur, in which the sulphide of copperincloses the gold, it must be thoroughly roasted until a concentration of the sulphide of copper has been effected and the iron has been separated from the copper. The ores, after having been thus prepared, are moistened with asufticient quantity of water to bring them into a loose woolly state, and in this state they are subjected to the action of hypochlorous acid. This acid is obtained by passing chlorine gas through a retort containing a concentrated solution of simple sulphate of soda, (NaO,SO By gently placed in earthen vessels or in casks lined with lead. If the action of the hypochlorous acid is completed, which can be ascertained if the smell of sulphurous acid stops, tepid water is passed through the ore and the auriferous lye is precipitated by introducing it in the form of a fine shower into a chamber filled with sul- The precipitate is collected and dissolved in aqua regia and the gold I PATENT is precipitated from this solution by the applia cation of sulphate of iron. j

Sulphureted hydrogen is produced by passing steam, or the gases emitted by burningum carbonized materials, through an oven contain .ing pyrites with imperfect circulation of air On account of this limited circulation of ai the carbonic oxide, having the greatest affinity for oxygen, burns first,whereas the hydrocar bons, by coming in contact with the sulphurous vapors rising from the pyrites, decompose j; and form sulphureted hydrogenl and carbon.l

The different effect produced by. theme of hypochlorous acid and of chlorine-gas (which;

is now used) will be apparent from the following observations: If chlorinej-gasfis brought in contact with the ore prepared as above I stated, the water used for moisteningthe ore is saturated with chlorine, and wherever it comes in contact with gold it dissolves the same. Toward the close of the operation sinr ple chloride of sulpl1ur(S,Gl)is formed,and 1. thereby the steam or vapor carried awayby} r the chlorine-gas is decomposed into hydrochloric acid, sulphur, and sulphurous acid. i As long as moist chlorine-gas *is present the sulphurous acid is transformed into sulphuric acid, andthehydrochloric acid, unlessbrought in direct contact with metal oxides or alkaline earths, absorbs chlorine;or, if no fresh chlorine is admitted, it forms sulphureted hydrogen whenbrought in contactwithlthe primary or secondary combination of sulphur. In. the H former case awaste of chlorine-gastakes place,., 1 r and in the latter a portion of. the chloride of gold already formed is decomposed and lost for the process. The effect is quite different, .1 if, instead of chlorine-gas, hypochlorous acid is used in treatingores. In this case notthe chlorine, but the oxygenis the acting element. If, it meets sulphurit transforms the same into the highest oxidized combination, and where 3. r the hypoch'lorous acid .isbroughtin contact 1 with hydrochlorous acid, a decomposition takes placeaccording to the following formula: GlO8rHCe HO8t2Gl. By the use-of the hydrochloric acid, therefore-or, more properly speaking, by the oxygen brought into action.i-- any loss of such acid orany separation of gold is avoided. It must be further remarked that r in using hypochloric acid the chlorine gas is p The use, in treating auriferous ores, and

particularly pyrite containing gold, of hypochlorous' acid, substantially in the manner herein set forth. 1

W. AD. OTT.

Witnesses:

M. M. LIVINGSTON; WM. F. MONAMARA. 

